let teachers = new Map();
teachers.set("grade 1", "Mrs Johnson");
teachers.set("grade 2", "Mr Bennett");
for (let [key, value] of teachers) {
console.log(key + ' = ' + value);
}
// grade 1 = Mrs Johnson
// grade 2 = Mr Bennett
for (let key of teachers.keys()) {
console.log(key);
}
// grade 1
// grade 2
for (let value of teachers.values()) {
  console.log(value);
}
// Mrs Johnson
// Mr Bennett
for (let [key, value] of teachers.entries()) {
console.log(`The ${key} teacher is ${value}.`);
}
// grade 1 = Mrs Johnson
// grade 2 = Mr Bennett